http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Aperture-Coupled Quarter-Wavelength Microstrip Antenna
Ikmo Park 한국정보과학회 1999 Journal of Electrical Engineering and Information Vol.4 No.1
The aperture-coupled quarter-wavelength microstrip antenna is described in this paper. The antenna is formed on a substrate above the ground plane by short-circuiting the microstrip radiating element with a shorting pin to the ground plane. The antenna is fed by microstrip feedline through an electrically small aperture. With this structure, the size of the antenna can be significantly reduced and it enables ease of manufacturing of the antenna. Measured return loss and radiation pattern as well as the computed results using the FDTD method are presented and discussed.
Ikmo Park,Huy Hung Tran,Son Xuat Ta 한국전자파학회JEES 2014 Journal of Electromagnetic Engineering and Science Vol.14 No.3
A wideband circularly polarized (CP) antenna with a single feed is proposed for use in global navigation satellite systems. Its primary radiation elements are composed of two orthogonal bowtie dipoles, which are equipped with double-printed vacant-quarter rings to allow direct matching of the antenna to a single 50-Ω coaxial line and to produce CP radiation. The crossed bowtie dipole is appropriately incorporated with a planar metallic reflector to produce the desired unidirectional radiation pattern as well as to achieve a wideband characteristic in terms of impedance matching and axial ratio (AR) bandwidths. The designed antenna was fabricated and measured. The prototype antenna with an overall 1.2-GHz frequency size of 0.48 λo×0.48 λo×0.25 λo produced a measured |S11|<-10 dB bandwidth of 1.05-1.79 GHz and a measured 3-dB AR bandwidth of 1.12-1.64 GHz. It also showed right-hand CP radiation with a small gain variation (±0.3 dB) and high radiation efficiency (>93%) over the operational bandwidth.
Single-Feed Composite Cavity-Backed Four-Arm Curl Antenna
Ikmo Park,Son Xuat Ta 한국전자파학회JEES 2014 Journal of Electromagnetic Engineering and Science Vol.14 No.4
A single-feed composite cavity-backed four-arm curl antenna is presented for use in global positioning system (GPS). Its primary radiating element is fed by a vacant-quarter printed ring, which helps the antenna directly match to a 50- Ω coaxial line and produce a good circular polarization (CP). The cavity-backed reflector is employed to improve the CP radiation characteristics in terms of 3-dB axial ratio (AR) beamwidth and minimum AR value. The optimized design with an overall size of 90 x 90 x 25㎣ (0.4725 λ? x 0.4725 λ? x 0.13 λ? at 1.575 MHz). results in a |Su|〈-10 dB bandwidth of 8.66%(1,514-1,651 MHz) and a 3-dB AR bandwidth of 2.23% (1,555-1,590 MHz). The antenna radiates a widebeam right-hand circular polarization and operates with a measured radiation efficiency greater than 90% within its impedance matching bandwidth.
Design of a Circularly Polarized Tag Antenna for Increased Reading Range
Chihyun Cho,Ikmo Park,Hosung Choo IEEE 2009 IEEE transactions on antennas and propagation Vol.57 No.10
<P>We introduce a novel circularly polarized tag antenna, consisting of a truncated patch, a shorting plate, and a ground plane, to increase the reading range while remaining in compliance with EIRP regulations. The reading range of the proposed tag is twice that of linearly polarized tags, due to the decreased polarization mismatch between the reader and tag antennas. An additional parasitic patch is loaded onto the structure to boost the reading range in the UHF RFID band. As a result, an average reading range of 8 m is achieved between 860 MHz and 960 MHz, compared to a range of about 3 m with conventional dipole tags.</P>
Characteristics of the Angled Printed Dipole Array Antenna with Different Numbers of Dipole Elements
Heesu Wang,Ikmo Park 한국전자파학회JEES 2020 Journal of Electromagnetic Engineering and Science Vol.20 No.3
This paper investigated the characteristics of series-fed angled dipole antennas as the number of dipoles increased from one to two, four, and eight. A parallel strip line printed on both sides of the substrate was used to connect angled printed dipoles of the same size in a series with equal spacing. As expected, although the gain increased as the number of dipoles increased, the impedance and gain bandwidths decreased. In addition, as the number of dipoles increased, the half-power beamwidth (HPBW) differences between the xz- and yzplanes decreased and the radiation pattern of the xz-plane became more symmetric. Antennas with one, two, four, and eight-dipole elements in a series were designed, and their peak gains were 5.0 dBi, 7.2 dBi, 9.4 dBi, and 10.4 dBi, respectively. The differences between the xz- and yz-plane HPBWs of the four antennas were 160.4°, 41.7°, 14.2°, and 5.3°, respectively. As the number of dipoles in the antenna increased, the differences between the HPBWs in the xz- and yz-planes decreased.
Chihyun Cho,Ikmo Park,Hosung Choo IEEE 2010 IEEE transactions on antennas and propagation Vol.58 No.9
<P>We propose a modified Wheeler cap method to accurately measure the radiation efficiency of patch antennas with multiple resonances by modeling their impedance as a high-order circuit model. The radiation efficiency is obtained from the power consumption ratio between the radiation and loss conductances using a circuit model we developed. Our technique is validated by measuring the efficiencies of a circularly polarized microstrip patch antenna and a triple-band microstrip patch antenna. The measurement results are in close agreement with those produced by simulations, whereas the Wheeler cap method with a series-(or parallel-) resonant circuit model is shown to be unreliable.</P>
Design of a Low-Profile, High-Gain Fabry-Perot Cavity Antenna for Ku-Band Applications
Truong Khang Nguyen,Ikmo Park 한국전자파학회JEES 2014 Journal of Electromagnetic Engineering and Science Vol.14 No.3
A Fabry-Perot resonator cavity antenna for Ku-band application is presented in this paper. The Fabry-Perot cavity is formed by a ground plane and a frequency selective surface (FSS) made of a circular hole array. The cavity resonance is excited by a single-feed microstrip patch located inside the cavity. The measured results show that the proposed antenna has an impedance bandwidth of approximately 13% (VSWR≤2) and a 3-dB gain bandwidth of approximately 7%. The antenna produces a maximum gain of 18.5 dBi and good radiation patterns over the entire 3-dB gain bandwidth. The antenna’s very thin profile, high directivity, and single excitation feed make it promising for use in wireless and satellite communication applications in a Ku-band frequency.